Greenpeace says the academics agreed to write the papers without knowing the source of the funding.

Greenpeace just proved how easy it is for the coal, gas, oil industry to buy off academics to write papers in favour of coal, oil and CO2, to cast doubt on science that points to climate change caused by industries.

Greenpeace activists went undercover, posing as representatives of oil and coal companies, to commission researchers to write a paper about the benefits of CO2.

The researchers in question belonged to Princeton and Penn universities. One of the researchers, Dr William Happer, the Cyrus Fogg Brackett Professor of Physics, Princeton University, was scheduled to speak at Senator Ted Cruz's Senate hearing on promoting climate denial.

Greenpeace reported that the academics agree to write the papers without knowing the source of the funding.

"In none of these cases is the sponsor identified. All my work is published as an independent scholar," said Professor Frank Clemente of Penn State.

Professor William Happer, a physicist and also a leading climate-sceptic academic, agreed to write a paper on the benefits of CO2, which was being paid for by a Middle East oil company and agreed to not disclose the source of the funding.

He also said he has testified for Peabody Energy for a state hearing after being paid thousands of dollars for it.

The Donors Trust is supposedly known as a "dark money ATM" which can siphon off money from fictional oil and gas companies in the Middle East to the US for think-tanks on climate scepticism.

Global Warming Policy Foundation, a UK-based climate-sceptic think tank, runs an unofficial peer-review process, which Happer wanted to run the paper by as it would be difficult to publish it in academic journals.

Frank Clemente was approached to write a paper "to counter damaging research linking coal to premature deaths (in particular the World Health Organisation's figure that 3.7 million people die per year from fossil fuel pollution)".

He said he would charge $15,000 for a paper of 8-10 pages, reports Energydesk.

The Greenpeace investigation exposed the academics, the process through which money was being pumped in for the papers and the peer-review process based in the UK that was validating the papers maligning climate science.